Unless you're trying to open files in the xlsx or xlsm formats, Excel 2003 should do just fine. Even then, unless you need access to features supported only by Excel 2007 & later (e.g. workbooks with more than 256 columns and/or 64K rows), installing the Office Compatibility Pack (
https://www.microsoft.com/en-us/down...ails.aspx?id=3) should suffice.